The Shortest Event Handler Syntax
Posted in Development
I don’t know how I missed this! In ASP.NET 1.x you wired event handlers as follows (assuming Submit is a button):
Submit.Click += new EventHandler(Submit_Click); … void Submit_Click(object sender, EventArgs e) { // Handle the click }
In 2.0, anonymous delegates come in handy when event handlers are short enough.
Submit.Click += delegate (object sender, EventArgs evt) { // Handle the click };
is the same is
Submit.Click += delegate { // Handle the click };
But I slapped myself on the forehead when I saw this “shorthand” syntax, which is equivalent to the first example:
Submit.Click += Submit_Click; … void Submit_Click(object sender, EventArgs e) { // Handle the click }
4 comments
Milan Negovan
on January 16, 2007
Shane, I don't think there's a difference. It should compile down to the same code. It's just a shorter notation and less typing.
ASPCode.net
on January 20, 2007
Cool! Didn't know that works for event handlers as well. I am just getting "used to" using delegates and anonymous functions for Collection.Find etc. Also thanks for Submit.Click += Submit_Click;
Shane Shepherd
on January 15, 2007
@Milan,
Let me see if I have this right...
In your code-behind you can put
Submit.Click += Submit_Click;
at the root of your class...and this handles the same job as a onclick="Submit_Click" in your .aspx page? If so, cool. Is there an advantage to either the programmatic or the declarative method of doing this?